Buspirone represents a new initiative in the treatment of anxiety. Conventional benzodiazepine anti-anxiety drugs, such as diazepam, cause ##STR3## physical dependence and sedation and interact with alcohol. Buspirone appears to lack these side effects. Buspirone, however, is not as efficacious as the benzodiazepines in patients who have had previous benzodiazepine therapy.
Buspirone is a partial agonist at the 5HT.sub.1A receptor, and this is thought to be the mechanism of its anti-anxiety activity, as disclosed by New, J. S., "The discovery and development of buspirone: A new approach to the treatment of anxiety", Med. Res. Rev., 10, 283-286 (1990). Buspirone was initially investigated as an anti-psychotic drug and binds to the D.sub.2 receptor. Thus, while buspirone offers important advantages as an anti-anxiety agent, a compound with greater receptor specificity and greater affinity for the 5HT.sub.1A receptor is desirable. Specifically, compounds which are anxiolytics and which are ligands at the 5HT.sub.1A receptor should have improved selectivity for the 5HT.sub.1A receptor versus the 5HT.sub.2, D.sub.2 and .alpha..sub.1 receptors.